Electrical contact arrangement and air insulated medium voltage circuit breaker including the electrical contact arrangement

Abstract

An electrical contact arrangement for medium to high voltage applications includes a contact arm having a distal end section on which a circular shaped annulus arrangement having several axially and parallel directed contact fingers is arranged. The contact fingers are pressed on the contact arm via respective radially directed connection sections by a spring ring which is peripherally arranged around the contact fingers. The distal end section of the contact arm includes a first ring-shaped surface and an adjacent second ring-shaped surface, so that the connection section of each contact finger is pressed to at least both the first and second ring-shaped surfaces.

What is claimed is: 
     
       1. An electrical contact arrangement for medium to high voltage applications, the electrical contact arrangement comprising:
 a contact arm having a distal end section; 
 a circular shaped annulus arrangement arranged on the distal end section of the contact arm, the annulus arrangement including a plurality of axially and parallel directed contact fingers; and 
 a plurality of radially directed connection sections arranged to press a corresponding one of the plurality of contact fingers on the contact arm by a first spring ring which is peripherally arranged around the contact fingers, 
 wherein the distal end section of the contact arm includes a first ring-shaped surface and an adjacent second ring-shaped surface, 
 wherein the corresponding connection section of each contact finger is respectively pressed to both the first and second ring-shaped surfaces, and 
 wherein the first ring-shaped surface and the second ring-shaped surface form a V-shaped groove on the distal end section of the contact arm. 
 
     
     
       2. The electrical contact arrangement according to  claim 1 , wherein the V-shaped groove corresponds to a curve-shaped connection section of each corresponding contact finger, respectively. 
     
     
       3. The electrical contact arrangement according to  claim 1 , wherein the V-shaped groove only corresponds with the first spring ring for pressing the contact fingers to the contact arm. 
     
     
       4. The electrical contact arrangement according to  claim 1 , wherein the V-shaped groove has an asymmetrical cross section. 
     
     
       5. The electrical contact arrangement according to  claim 1 , wherein the contact arm is composed of one of copper and aluminum. 
     
     
       6. An air insulated medium voltage circuit breaker comprising:
 at least one electrical pole part which is electrically connected to at least one of a pushbar terminal and a cable terminal by an electrical contact arrangement according to  claim 1 . 
 
     
     
       7. The electrical contact arrangement according to  claim 1 , wherein the first ring-shaped surface and the second ring-shaped surface form an L-shaped groove on the distal end section of the contact arm. 
     
     
       8. The electrical contact arrangement according to  claim 7 , wherein the L-shaped groove corresponds to a rectangular-shaped connection section of each corresponding contact finger, respectively. 
     
     
       9. The electrical contact arrangement according to  claim 1 , wherein the first spring ring is an outer spring ring configured to press the corresponding connection sections of the contact fingers to the first ring-shaped surface, and
 wherein the electrical contact arrangement comprises a second spring ring configured to press the corresponding connection sections of the contact fingers to the second ring-shaped surface. 
 
     
     
       10. The electrical contact arrangement according to  claim 9 , wherein at least one of the first spring ring and the second spring ring is formed as a spiral spring. 
     
     
       11. The electrical contact arrangement according to  claim 9 , wherein the first ring-shaped surface and the second ring-shaped surface form an L-shaped groove on the distal end section of the contact arm, and
 wherein the L-shaped groove corresponds with the first spring ring and with the second spring ring for pressing the contact fingers to the contact arm. 
 
     
     
       12. The electrical contact arrangement according to  claim 9 , wherein the second spring ring is arranged as a washer spring for generating an axially directed pressing force to the contact fingers. 
     
     
       13. The electrical contact arrangement according to  claim 9 , wherein the first ring-shaped surface and the second ring-shaped surface form an L-shaped groove on the distal end section of the contact arm, and
 wherein the electrical contact arrangement includes a screw element axially screwed into a front side of the contact arm to attach the second spring ring to the second ring-shaped surface of the L-shaped groove. 
 
     
     
       14. The electrical contact arrangement according to  claim 9 , wherein the first ring-shaped surface and the second ring-shaped surface form an L-shaped groove on the distal end section of the contact arm. 
     
     
       15. The electrical contact arrangement according to  claim 14 , wherein the L-shaped groove corresponds to a rectangular-shaped connection section of each corresponding contact finger, respectively. 
     
     
       16. The electrical contact arrangement according to  claim 14 , wherein the L-shaped groove corresponds with the first spring ring and with the second spring ring for pressing the contact fingers to the contact arm. 
     
     
       17. The electrical contact arrangement according to  claim 14 , comprising:
 a screw element axially screwed into a front side of the contact arm to attach the second spring ring to the second ring-shaped surface of the L-shaped groove.